The present invention will now be described in relation to cable-barriers for use in relation to roading networks. However, this should not be seen as limiting, as aspects of the present invention may also have application in relation to different fields.
Existing cable-barriers which employ a cable assembly as part of the barrier have a variety of different ways for anchoring the cable assembly to the ground, at the terminal ends of the cable-barrier. Typically, the cable(s) employed in the cable-barrier are guided through one or more terminal posts and are inclined towards one or more ground anchor points.
However, one problem with existing anchoring systems is that the inclined nature of the cable(s) at the terminal end of the barrier, together with the integrity of the anchoring system, acts to effectively create a ramp when impacted by an errant vehicle. As a result, the impacting vehicle either rolls or becomes at least partially airborne, following an impact.
Some existing cable-barriers, such as the cable-barrier system manufactured by Gibraltar, have attempted to overcome this ‘ramping’ problem by having their cables anchored to the ground via a quick release mechanism. Information regarding the Gibraltar system cable-barriers can be found on http://safety.fhwa.dot.gov/roadway_dept/road_hardware/index.htm.
However, one draw back of existing cable-barrier systems is that the anchoring systems only function in one direction. If a vehicle impacts the cable-barrier in the other or ‘reverse’ direction, snagging of the vehicle between the cables can occur, which in turn causes substantial damage to the vehicle and potentially more harm to the driver. Another drawback of existing cable-barriers is that if hit in the ‘reverse’ direction, ramping of the vehicle may still occur.
In the inventors experience, no such quick release mechanism has been fully effective at reducing or preventing an inclined cable anchoring system from acting as a ramp or snag, during impacts from a number of different angles, particularly ‘reverse’ direction impacts—these are impacts that occur in a direction other than a substantially head on impact.
It would therefore be useful to have a cable-barrier system or release mechanism that could withstand impact from collisions from both directions. Additionally, it would also be useful to have a cable-barrier which can release the anchor-cable downwardly extending from the terminal post of a cable-barrier, in situations where the anchor-cables are capable of acting as a ramp or snag during a collision.
It is an object of the present invention to address the foregoing problems or at least to provide the public with a useful choice.
All references, including any patents or patent applications cited in this specification are hereby incorporated by reference. No admission is made that any reference constitutes prior art. The discussion of the references states what their authors assert, and the applicants reserve the right to challenge the accuracy and pertinency of the cited documents. It will be clearly understood that, although a number of prior art publications are referred to herein, this reference does not constitute an admission that any of these documents form part of the common general knowledge in the art, in New Zealand or in any other country.
It is acknowledged that the term ‘comprise’ may, under varying jurisdictions, be attributed with either an exclusive or an inclusive meaning. For the purpose of this specification, and unless otherwise noted, the term ‘comprise’ shall have an inclusive meaning—i.e. that it will be taken to mean an inclusion of not only the listed components it directly references, but also other non-specified components or elements. This rationale will also be used when the term ‘comprised’ or ‘comprising’ is used in relation to one or more steps in a method or process.
Further aspects and advantages of the present invention will become apparent from the ensuing description which is given by way of example only.